Metal finishing Q&As since 1989

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Suitable bath for hard anodising

2007

DEAR FRIENDS

FOR HARD ANODISING THERE ARE 3 PROCESSES AVAILABLE:
1. sulfurIC ACID
2. sulfurIC OXALIC BATH
3. CHROMIC BATH.
WHICH BATH GIVES BETTER HARDNESS, MICROSTRUCTURE.
PLEASE GIVE SPECIFIC APPLICATIONS OF EVERY BATH & ADVANTAGES & DISADVANTAGES OF EACH BATH OVER THE OTHERS.

THANKS GOOD DAY

PRASAD

Prasad Patwardhan
- AHAMADNAGAR

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Hi Prasas. I am personally not familiar with chromic acid hard anodizing. The chromic acid anodizing that I am familiar with produces a very thin coating rather than the thick coatings associated with hard anodizing. Please tell us something about this chromic acid hard anodizing process.

If you can please post the details of your own specific and limited situation, we may be able to help you select which type of anodizing to specify. But all the advantages and disadvantages of competing technologies, including typical applications, require dozens of "ifs, ands, and buts", so answers must usually be offered at book length rather than within the few paragraphs appropriate to a public forum. The Surface Treatment of Aluminum and Its Alloys probably answers that kind of question. Good luck.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2007